Why do they need to reboot Metra trains?

Very often, I get to my outbound Metra train at Union Station, 10 minutes early, or even a bit more. While I am getting on and taking my seat in the mostly empty train car, the lights are on, air conditioner / heater / whatever all seem to be running.

However, almost always, a short while before they depart the station, they seem to “shut down” the train car (all the lights except emergency lights go out, air conditioner goes out, etc.) This lasts maybe a minute or so, and then everything comes back on. Another few minutes later we depart. I don’t have exact times, just gut guestimates.

Anyone know why they do this? :confused:

Thanks!

You know, they do this on the Amtrak trains leaving Union Station too. I’ve been wondering this myself.

the motive engines which move the train and power everything aren’t run while the train is standing.

The same thing happens in planes when they switch from airport power to airplane engine power.

Yup. While the trains are standing in the station, they’re plugged into power supplies at the station, which keep the lights on and the air / heat running. Shortly before departure, they unplug the connection to the in-station power supply, and bring the diesel generators in the locomotive up to full power. The “blackout” period you briefly get a few minutes before departure is that switchover.

As I understand it, this is done to cut down on the diesel exhaust levels in the platform area, as well as to conserve some diesel fuel.